Cellular communication systems employ a plurality of antenna systems, each serving a sector or area commonly referred to as a cell. The collective cells make up the total service area for a particular wireless communication network.
Serving each cell is an antenna and associated switches connecting the cell into the overall communication network. Typically, the antenna system is divided into sectors, where each antenna serves a respective sector. For instance, three antennas of an antenna system may serve three sectors, each having a range of coverage of about 120°. These antennas typically have some degree of downtilt such that the beam of the antenna is directed slightly downwardly towards the mobile handsets used by the customers. This desired downtilt is often a function of terrain and other geographical features. However, the optimum value of downtilt is not always predictable prior to actual installation and testing. Thus, there may be a need for custom setting of each antenna's downtilt upon installation of the actual antenna. Typically, high capacity cellular type systems can require re-optimization during a 24 hour period.
U.S. Pat. No. 6,924,776 describes a base station antenna with a plurality of ground planes configured in a staircase arrangement, and an array of dipole antenna elements disposed adjacent to the ground planes. A first problem with the arrangement of U.S. Pat. No. 6,924,776 is that the ground planes are expensive, bulky and heavy. A second problem is that the edges of the steps in the ground plane can cause undesirable diffraction effects.